The present disclosure generally relates to the field of eye tracking. In particular, the present disclosure relates to systems and methods for generating and/or using gaze tracking data indicating a gaze direction of an eye.
Several different eye tracking systems are known in the art. Such systems may for example be employed to allow a user to indicate a location at a computer display by looking at that point. The eye tracking system may capture images of the user's face, and then employ image processing to extract key features from the user's face, such as a pupil center and glints from illuminators illuminating the user's face. The extracted features may then be employed to determine where at the display the user is looking. Naturally, factors such as accuracy, speed, and reliability/robustness of the eye tracking are desirable to achieve a positive user experience. Therefore, several schemes have been proposed for mitigating the negative effects of different types of errors or inaccuracies that may occur in eye tracking systems.
For example, US 2010/0328444 A1 (which is incorporated by reference herein in its entirety) discloses an eye tracker which includes at least one illuminator for illuminating an eye, at least two cameras for imaging the eye, and a controller. The configuration of the illuminator(s) and cameras is such that, at least one camera is coaxial with a reference illuminator and at least one camera is non-coaxial with a reference illuminator. The controller is adapted to select one of the cameras to be active to maximize an image quality metric and to avoid obscuring objects. The eye tracker is operable in a dual-camera mode to improve accuracy. A method and computer-program product for selecting a combination of an active reference illuminator from a number of reference illuminators, and an active camera from a plurality of cameras are also disclosed.
As another example, US 2014/0362446 A1 (which is incorporated by reference herein in its entirety) discloses a head mountable display (HMD) system. The HMD system comprises an eye position detector comprising one or more cameras configured to detect the position of each of the HMD user's eyes, a dominant eye detector configured to detect a dominant eye of the HMD user, and an image generator configured to generate images for display by the HMD in dependence upon the HMD user's eye positions. The image generator is configured to apply a greater weight to the detected position of the dominant eye than to the detected position of the non-dominant eye. The dominant eye is detected by one or more of the following: (i) the eye with the wider range of movement, (ii) the eye which reaches a gaze direction appropriate to a displayed stimulus the closest and/or the most quickly, (iii) the eye which holds a position relating to a displayed stimulus.
As a further example, US 2016/0004303 A1 (which is incorporated by reference herein in its entirety) discloses an eye gaze tracking system which includes a gaze data acquisition system including a plurality of light sources and a plurality of image sensors. The light sources are arranged to emit light to a head of the user, and the image sensors are configured to receive the light. In an embodiment, the system further includes a gaze tracking module including an ocular feature extraction module, a point of regard (POR) calculation module and a POR averaging module. The ocular feature extraction module is configured to process the gaze data and to extract ocular features in relation to each image sensor, and is configured to determine a confidence value associated with an accuracy of the parameters for each image sensor. The confidence value may for example depend on head pose angle (in yaw, pitch and roll angle), user distance and feature detection reliability. The POR calculation module is configured to determine a POR from the ocular features for each image sensor. The POR averaging module is configured to determine an average POR using the confidence values of the POR for the respective image sensors.
However, it would be desirable to provide further systems and methods addressing at least one of the issues described above.